Principles of marine degradation 1

contents and introduction

Environmental degradation has become the most
serious threat to the health of our seas, particularly to our coastal seas.
But because it is so difficult to see, while progressing only slowly, most
people and scientists have remained obtuse (= blind to the obvious).
For instance, practically no scientific research has been done anywhere
in the world, into how degradation works or how it can be measured. This
large chapter therefore attempts to put my personal thoughts and observations
into a coherent framework that may perhaps become the beginning of a new
and eventually large discipline of science. Please note that this whole
chapter covers entirely my own findings and speculations, since no references
can be found in either the scientific literature or textbooks. If you are
neither a diver nor a scientist, you may still find this chapter fascinating,
because in the end, degradation will affect your life and even more so
that of your children. Although the principles outlined here are universally
applicable, I have from necessity, restricted myself to examples from New
Zealand seas. This chapter will grow as new insight is gained.

The naturalist's achievement is first and
foremost a personal one, a state of mind representing a profound understanding
of and with the natural world. It cannot be shared like the predictive
power of a scientific theory. Nevertheless this understanding is among
the precious and extraordinary qualities which justify human existence.
- R H Peters (1992)

.
this long chapter consists of 4 parts: part1(contents),
part2,
part3,
part4
according to their colours

Many organisms display a kind of unhappiness
or ill health before dying. These are important warnings as they are visible
on organisms which have not yet disappeared and which may recover without
surrendering their space.

As degradation intensifies, it manifests itself in more and more symptoms.
The timeline chronicles degradation events and when symptoms were first
seen. The timeline has been placed in a separate document because it is
updated regularly and relates only to the situation in New Zealand. Only
reading is believing! (4 pages)

examples

This chapter has restricted itself to the principles
of degradation without giving many examples. Follow the documents below
to familiarise yourself with the various visual aspects of degradation.
This section will grow as more images become available. For now, just imagine
the outcry of indignation had these images come from our National Parks!decay: many
photographic examples in several chapters, richly annotated (large)

related pageson this web site

Read the important chapters below to gain a more thorough
understandingSoil: a large
section on the origins, functioning, sustainability and loss of soil. Very
important.(large)Resource management: understanding
stressors and resilience and much more. (28p)Biodiversity: understanding
the variety of life and how the sea differs from the land. (32p)Introduction
to habitats: understanding what it means to live in the sea. (14p)Principles of conservation:
understanding threats and their remedies and why many won't work. (30p)Marine conservation: principles
of marine conservation and differences between land and sea. (34p)The intertidal
rocky shore: principles and factors, illustrated by many examples and
species. (80p)The plankton
balance hypothesis: how plankton feeds and kills, and what this
means. Very important to understand degradation. (10p)The Dark Decay Assay:
a new method to measure the activity of planktonic decomposers, enabling
amateurs to measure degradation in lakes, rivers and the sea. Read how
the most important ecological laws of this planet were discovered using
the DDA. The sea does not work as previously thought! Only reading is believing!

Internet links

scirus Elsevier's
impressive science search engine to find science done on degradation. Try
if you can find any, preferably before publication of this chapter (2004).

IntroductionDegradation of the sea is not new, since it has been with us for as
long as Man changed his environment. But in recent times it has been accelerating
because of the multiplying effect of increases in populations, wealth and
wastes. To feed more people better, we need more arable land and more water
for irrigation. Although agricultural engineering has produced better crops,
these also need more fertiliser and pesticides. At the dawn of genetic
engineering (GE), we can only guess at the benefits expected of it. But
for now we must assume that for many years to come, it will be 'business
as usual' and the many problems negating previous progress appear to be
accelerating.

But there are also compounding effects. As more and more forests were
converted to arable lands, it changed the world's weather and climates
quite profoundly, resulting in even more problems. Everywhere in the world
the weather now oscillates between larger extremes of heat, drought, flooding
and so on. Such fluctuations do not help sustainability, reason why the
soils of our Earth are washing into the seas at an ever increasing rate.

Most of the heat transferred from equator to poles and from sea to the
continents happens by winds laden with moisture. Because of the enormous
amounts of energy locked up and released by evaporation, condensation and
rainfall, air circulation takes care of over 60% of all heat transport
on Earth. The remaining part is done by ocean currents. Because of the
short-circuit
in the water cycle (due to deforestation), less moisture reaches
the centres of continents and less heat is dispersed this way, resulting
in extremes in temperatures and drought. At the same time, winds increase
their intensity (due to higher temperature differences), travelling mainly
along continental margins where rains become heavier. These combined changes
in weather all over the world bring with them large increases in erosion.
In NZ the problem has been exacerbated by the sudden abolishment of subsidies
on fertiliser in 1986.

The stable soils of the world that have been cultivated for a long time
(many centuries) are not causing undue problems, but as good land became
scarce, more marginal lands were opened up in places that were either too
steep, too wet, too dry, too hot or too cold. After 50 years (typically)
such lands become 'tired' and turn into wastelands with little cover, ready
to be washed away into the sea. New Zealand is a classic example of this.
Only recently have estimates been made of the soil loss in our country,
amounting to over 270 million tonnes per year. But my own observations
have shown the amount of soil loss almost to be doubling each decade since
the subsidy on fertiliser was abolished in 1986. It was the reason for
establishing Seafriends and writing this web site while researching 'Why
are we losing so much so fast?'. Please read the soil
section to quickly inform yourself.

Soil
statistics for New ZealandThe following statistics
aim to illustrate the problem with soil loss in New Zealand. Total land
area: 27,050,000ha. Soil loss estimated at 270 million tonnes per year
or 10t/ha which is about 5-10 times the sustainable rate of 1-2 t/ha. New Zealand loses between
200 and 300 million tonnes of soil to the oceans every year. This rate
is about 10 times faster than the rest of the world, and accounts for between
1.1 and 1.7 percent of the world's total soil loss to the oceans, despite
a land area of only 0.1 percent of the world's total. [1]

The use of Synthetic fertiliser
consumption is up 21% during 1996 to 2002. The Nitrogen fertiliser urea
consumption is up 160% during 1996 to 2002. [2]Land under irrigation is
increasing at a rate of around 55% nationally each decade [3]

Most rivers in farming areas,
particularly in lowlands, generally fail to meet recommended guidelines
as a result of contamination from increased nutrients, turbidity and animal
faecal matter. [1]

New Zealand soils were formed
under very slow metabolising forests, resulting in deep B and C horizons
(subsoils). Correspondingly, natural erosion was very low, and rivers,
lakes and seas clear. NZ aquatic and marine organisms have evolved in clear
waters, reason that they are affected so much today. [4]

Deep
soils in New ZealandNew Zealand has a number
of problems arising from its unique situation. Over 60 million years of
isolation has given it the non-deciduous Podocarp forests that grow
slowly while producing persistent leaf litter which decomposes only slowly.
Its mild sea climate produces rain in all seasons, such that soils developed
in a continuum of available moisture. As a result, deep subsoils developed
underneath the native forests and because of this depth, these subsoils
also formed slowly above the underlying bedrock. Natural erosion was unusually
low and the marine organisms of NZ evolved in these conditions of clear
seas.After deforestation, the
top soils provided a rich matrix for grasslands but these top soils eventually
thinned, depending on slope and available moisture. As the top soils thinned,
the natural fertility was lost and fertilisation became more than necessary.
Eventually the subsoil became bare, allowing rain drops to impact directly
on the subsoil loams. From here on erosion accelerated rapidly with consequent
problems in the sea. Then in 1986 the subsidy on fertiliser was abolished,
resulting in underfertilisation of hill country, and a rapid increase in
soil loss.Another important factor
is the environment's ability to absorb moisture. Native forests retained
water on leaves, bark and the very porous top soil. The temperate loams
are also able to absorb moisture inside the layered crystal structure of
clay. Once forests became pastures, the ability of the environment to store
moisture diminished considerably, resulting in increased run-off with associated
gully and river erosion. Now the soils are exposed to repetitive cycles
of wetting and drying, which is detrimental to soil fertility while also
accelerating soil loss.

Is
it really serious?It is human nature to remain obtuse (=blind to the obvious) until bad
times knock on one's own door. The calls of visionaries and those who have
a keen sense of perception remain unheeded as also newspapers do not wish
to bring bad news for their advertising revenues. We also have grown used
to our problems going away due to the concerted efforts of scientists and
the application of new technology. Why should we be worried?
The fact that none of our existing mainland marine reserves are working,
as they are all degrading, is carefully hushed up and funding is not made
available for studying the new threat from degradation. The diagram shown
here was compiled from information in a scientific study done for the Department
of Conservation (DSIS142), which cost the tax payer over NZ$280,000. It
was done to show that marine reserves are working because snappers (Chrysophrys
auratus) return after a complete ban on fishing in the Poor Knights
Islands, located about 20km out in sea, in late 1998 (after the first sample
on the diagram).

This diagram shows the abundance of the fish that normally belong to the
Poor Knights and breed there. These are not seasonal stragglers or migratory
fish. Scientists counted the number of fish in a 125 square metre transect,
which equals roughly the size of a tennis court. Notice the use of three
different scales, but the picture is undeniable: fish are disappearing.
This is what we have been seeing for over fifteen years as also the water
quality deteriorated. Remember that this is the best of our coastal marine
reserves, so it takes little imagination how all the others fare. Yet the
scientists who collected and published this information, did not notice
it and mentioned not one word about it in their report! Note how sweep
(Scorpis
lineolatus) are increasing their numbers, as these really belong to
near-coastal waters, demonstrating that the water quality at the Poor Knights
is deteriorating alarmingly. So, should we be alarmed if even our best
marine reserve located on the edge of the continental shelf, is helplessly
degrading?

In a recent study, marine scientists quantified
coastal marine communities in 13 marine reserves spanning the length of
New Zealand. They looked at algal communities and their grazers, particularly
the green sea urchin
Evechinus chloroticus. They also noted environmental
variables such as slope of the substrate (rock) and made an estimate
of the fetch (distance over open water) as a measure of wave exposure.
To their credit, they also included degradation variables of Secchi
disc visibility (the opposite of turbidity) and the percentage
sediment
cover. They also included the maximum transect depth even though
they did not dive deeper than 12m. Their most important result is the proof
that degradation (=turbidity + sediment) is by
far the most decisive factor on what grows where. In other words, the
seascape cannot be understood without understanding degradation.

Yet it took us over 15 years of prodding to get them interested in this
very important phenomenon! Note how the presence of sea urchins also plays
a role (of course) but that marine reserves have practically no effect
at all, proof that they do not save the environment against degradation.
Why did the report not mention these points?